Question

What is the ultimate source of energy for organisms?

Answer 1

The sun

Explanation:

The sun is the biggest and renewable source of energy to all organisms. It does that in the form of light energy. However, that energy must be converted to other forms of energy that are suitable to organisms.

Every second, the sun produces around `3.8 xx 10^26 \ "J"`, but only `1.74 xx 10^17 \ "J"` manage to reach the Earth. That is still a lot of energy!

Source:

http://www.learnastronomyhq.com/articles/how-much-energy-does-the-sun-produce.html

Answer 2

Sun

Explanation:

Sun is the ultimate source of energy. Plants & other photosynthetic organisms take energy from the sun to make food and this food is eaten by us and ultimately we get energy.
Hence, sun is the ultimate source of energy.